Find all vectors u that satisfy the equation: ⟨1, 1, 1⟩ ⋅ u = ⟨-5, 4, 1⟩.
a) ⟨3, 2, 4⟩
b) ⟨-4, -1, -3⟩
c) ⟨-2, 3, -5⟩
d) ⟨1, 1, 1⟩